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Hairline Crack Repair?

Discussion in 'Fish Taxidermy' started by 1fish2fish, Jun 25, 2012.

  1. 1fish2fish

    1fish2fish Well-Known Member

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    Good evening everyone,

    Just wondering if anyone has dealt with a hairline crack in a painted blank. I've got an ARP 3-D that has a couple hairline cracks at the rear of the head and the head-body junction. I didn't see them in the primed blank, but when I layed down my base colors, they are as clear as day. I could have easily fixed them before I started painting, but its too late for that. I could strip the thing and start over, but thought I'd see if anyone had a good solution from their own experience. My best thought was to put some fin magic over the cracks, and layer on more color, but I can never get that stuff really smooth. Anyway, I'd appreciate any wisdom you have on this problem.

    Thanks, Scott
     
  2. den007

    den007 Active Member

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    You might try a quick set epoxy (one minute is even available). Use a toothpick or thin tool to run it along the crack.....smooth out with a brush and safety solvent. When it hardens up good, very lightly sand and repaint. There are also some fairly quick set clear urethanes that might do the trick.
     

  3. Brian W

    Brian W Well-Known Member

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    Denny got it right to feather sand when dry and then blend in the paint. Simple fix. I use Magic Smooth. Smooth out with a wet finger. It smooths so fine that you may need very little sanding if you do it right..........no problem.
     
  4. 1fish2fish

    1fish2fish Well-Known Member

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    Thanks guys. Logical. I'll give it a try. I've got some extra Loctite Quick Set Epoxy from a home project.

    Brian, do you use Magic Smooth on all your seam work? I used to use the epo grip seam repair putty, but it takes forever to dry it seems (no pun intended); though I do like alot of their products a great deal. I haven't found anything for regular seam work that I'm in love with. I've heard a few good coments about Magic Smooth that have me considering buying some.

    Best,
    Scott
     
  5. George

    George The older I get, the better I was.

    PERSONALLY, I don't use the epoxy clear pastes to repair cracks. Both the fast setting liquid and the pastes have a tendency to migrate or seep down into the crack. I use the Epo-Grip #30 paste. A long curing epoxy has much greater holding power than fast setting ones and they tend to stay static. The #30 can be used just like the clear paste but it the crack is covered before its cured, it will stay covered afterwards as well and bonding the split together better. It can be worked with a wet finer just like the Smooth Out or the Clear Paste from Epo-Grip. The best part is that after about 3 hours, the epoxy becomes tacky and can be formed or patterned to recreate scale detailing. It does take 6 hours to complete cure, but it's permanent.
     
  6. 1fish2fish

    1fish2fish Well-Known Member

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    Thanks George, good tip. I wasn't sure if a liquid Epoxy would seep, leaving a gap needing additional coats. These cracks are really hairline thin, but I don't want to clean up the paint job, only to find I still have a crack line. I knew fin magic wouldn't seep, but as I said, I never get a clean transition from repair to body without work that would damage the paintjob. I just looked the #30 paste up on the Epo-Grip website. ( http://www.epogrip.com/furn/furn_epo_grip_slow_set.htm for those interested). Looks like a product I'll have to try for a few applications.

    Best, Scott
     
  7. Brian W

    Brian W Well-Known Member

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    Scott,
    I use Magic Smooth for seam work and shrinkage. I like how nice is smooths out, dries rock hard, doesnt shrink or crack, and sands easily. It dries almost translucent which is an easier color to blend than clay for me. I've done some stuff on the show side of fish you cant tell I repaired. Doesnt dry real fast but I like that. I can check my application in a half hour or so and if I see its needs more feathering (because you know on the white part of a fish, you'll see every wrinkle) I use a wet finger and feather a little more. Most times, I dont even need to sand after it dries.
    The key is knowing how to feather/move the stuff. A dryer (not totally dry) finger will pull it in the direction you want it to go and then a wet finger smooths it out with no travel. I would not mount a fish without that stuff. Period.
     
  8. FishArt

    FishArt Well-Known Member

    Well, maybe it's just me but I would be concerned as to how deep those cracks go. IMO, covering it with anything w/o any prep work is flipping a coin. They could resurface again down the road. What I would do (since the top of the head area is relatively easy to blend) is I would grind down the cracks with a sanding disk/dremmel until I no longer saw any cracks. Fill and blend with APoxie Sculpt. Repaint/Blend the top of the head/transition area. A pretty easy fix actually for most species and how detailed the paint is up top...
     
  9. Brian W

    Brian W Well-Known Member

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    Marty...It IS YOU.....lol. Its a hairline crack dude. Other than a scuffing up to insure adhesion, that cracks not going anywhere with a simple repair.......you start grinding down a crack to eliminate it and you make extra work for yourself.......ooops, I forgot you get paid by the hour..... ;D
     
  10. FishArt

    FishArt Well-Known Member

    Brian, I guess the reason I would err on the more work side is because of the location. I'm not sure if the Arp blanks are rotocast or not. But, if not then the head was molded separately and attached. Hairline cracks at the head juncture (the weakest link) COULD mean the area was stressed in shipment. Those hairlines could be deeper than you think. Or not. You just don't know. If they are deeper and you just scuff it up then there's a good chance they will be back down the road. I guess the question I have is if you're scuffing the area up, you have to sand and repaint anyway, right? If that's the case, what's the difference between sanding the area down to ensure it's all good, apoxie sculpting and then repainting? What are we talking here, maybe 5 minutes extra? But then you KNOW it's not going to come back to haunt you. JMO...
     
  11. George

    George The older I get, the better I was.

    Marty, forgive Brian, he thinks he's on a roll. LOL

    Your suggestion is the only failsafe out there. That's the way we repaired aircraft parts. It's just safer to open up the hairline crack to insure that it's repaired at the source.

    Brian, Smooth Out and Epo-Grip Clear Paste are the same products. AND THEY MIGRATE. The #30 has the SAME CONSISTENCY but will NOT migrate. Instead of the "clear" or white appearance, the #30 cures to a slight tea stained appearance.

    Still for you fish officianados, cutting that crack out - perhaps just cutting a small groove under the cracked surface, and then filling that void will insure that the crack won't ever reappear down the road. Good suggestion Marty.
     
  12. 1fish2fish

    1fish2fish Well-Known Member

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    Hey, I really appreciate the help everyone. I wish I knew more about epoxies (and resins for that matter) in terms of both chemical and performance characteristics. Glad you all took the time to share your knowledge and experience with me. Its made me think a bit more about what to do. I certainly never considered liquid quick-set epoxy not holding up and the crack re-appearing. While I still feel I'll be free and clear with a fast setting liquid, I now think I better grind that sucker down and rebuild for security. I'm not sure what stresses could open the cracks back up. I'm thinking temperature (&humidity?) and physical handling of the replica are the main concerns, right? Anyway, thanks again.
    Best, Scott
     
  13. Brian W

    Brian W Well-Known Member

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    You guys are on hairline "crack" or something..... ;D....Magic smooth MIGHT migrate in the crack (what you what) but for the most part stays where you put it. It's the consistency of vaseline George. Dont think we are talking about the same product.
    Magic Smooth dries to a slight tea color also, not that it makes much a difference. I like magic smooth the most around fin butts as I have more control in the transition appearance opposed to fin magic which gives me less time to adjust and sculpt, which dries extremely opaque. I like the semi-translucent tea color also as it looks more natural and in most cases, needs very little paint or rub to blend. JMO.
     
  14. Steven Klee

    Steven Klee Steven Klee Studios

    Hey Scott,

    If it's hairline try flexing the the head on the body with moderate pressure. If the cracks open more you need to rethink strategies. If it seems really solid and stable, then I'm with Dennis M. on this one. A HIGH grade fast set epoxie is what I would recommend. Anything from Epo grip in fast set will work well. Fin Magic, Clear paste adhesive, Epo grip seam and repair putty etc. Smooths super easy with soapy water finger, No sag, dries fast and clear in 8 - 12 min so you can repaint sooner and get on with your project. It is more expensive, but is way better than cheaper walmart brand epoxies. Try it, you will like it.
    best, Steve
     
  15. 1fish2fish

    1fish2fish Well-Known Member

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    Steven,
    Thanks for chiming in. I have pulled pretty hard on the gill flap, which is where one of the cracks starts. That crack may have some slight travel. The others have 0 movement. I was kind of hoping the whole head would pull off so I could have peace of mind that there was a significant manufacturing problem with that union or severe mishandling of the blank. It seems pretty solid, so I'm not sure why they are there. Guess, I'll just fix them up. I may grind the crack out a bit and fill the valley with fin magic or apoxie sculpt after all, since I have them on-hand. Is the problem with the Home-Depot brand quick epoxies the addition of solvents? Anyway, I'll be buying a few of the products you guys are using to try out in the future. Just wish I had seen the cracks before I started painting.
    Best, Scott